:root{--bg:#fff;--fg:#1e293b;--h:#0f172a;--muted:#475569;--line:#e2e8f0;--card:#fff;--hero:#eff6ff;--soft:#f8fafc;--code:#f1f5f9;--blue:#1d4ed8;--blue2:#1e40af;--link:#1d4ed8;--field:#fff;--res:#eff6ff}
html.dark{--bg:#020617;--fg:#e2e8f0;--h:#fff;--muted:#94a3b8;--line:#1e293b;--card:#0f172a;--hero:#0b1224;--soft:#0f172a;--code:#1e293b;--blue:#2563eb;--blue2:#1d4ed8;--link:#60a5fa;--field:#020617;--res:#1e293b}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);font-family:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;line-height:1.5;-webkit-font-smoothing:antialiased}
a{color:inherit}:focus-visible{outline:2px solid var(--blue);outline-offset:2px}
.wrap{max-width:64rem;margin:0 auto;padding:0 1rem}.w4{max-width:56rem;margin:0 auto;padding:0 1rem}.w3{max-width:48rem;margin:0 auto;padding:0 1rem}
header.top{border-bottom:1px solid var(--line);background:var(--bg)}
header.top .wrap{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.5rem 1.5rem;padding-top:.75rem;padding-bottom:.75rem}
.logo{display:flex;align-items:center;gap:.5rem;font-size:1.25rem;font-weight:700;text-decoration:none;color:var(--h)}.logo svg{width:2rem;height:2rem}
nav{display:flex;flex-wrap:wrap;align-items:center}nav a{padding:.5rem .75rem;border-radius:.5rem;font-size:.875rem;font-weight:500;text-decoration:none;color:var(--muted)}nav a:hover{background:var(--soft);color:var(--link)}
.navrow{display:flex;align-items:center;gap:.25rem}
.icon{width:2.25rem;height:2.25rem;border:0;background:none;border-radius:.5rem;cursor:pointer;color:var(--muted);display:inline-flex;align-items:center;justify-content:center}.icon:hover{background:var(--soft)}
.icon svg{width:1.25rem;height:1.25rem}.icon .sun{display:none}html.dark .icon .sun{display:block}html.dark .icon .moon{display:none}
.hero{border-bottom:1px solid var(--line);background:var(--hero)}.hero .w4{padding-top:2rem;padding-bottom:2rem}
h1{margin:0;color:var(--h);font-size:2rem;font-weight:700;letter-spacing:-.02em;line-height:1.2}.hero h1.big{font-size:2.5rem}
.lead{margin:.75rem 0 0;max-width:42rem;font-size:1.125rem;line-height:1.75;color:var(--muted)}
.card{background:var(--card);border:1px solid var(--line);border-radius:1rem;box-shadow:0 1px 2px rgba(0,0,0,.05)}
.calc{margin-top:1.5rem;padding:1rem}
.tabs{display:flex;flex-wrap:wrap;gap:.5rem}
.tab{border:1px solid var(--line);background:none;color:var(--muted);padding:.5rem 1rem;border-radius:999px;font:inherit;font-size:.875rem;font-weight:500;cursor:pointer}.tab:hover{border-color:var(--blue)}
.tab.on{background:var(--blue);border-color:var(--blue);color:#fff}
.grid{display:grid;gap:.75rem;margin-top:1.25rem}
label{display:block;margin-bottom:.25rem;font-size:.875rem;font-weight:500;color:var(--muted)}
.field{width:100%;border:1px solid #cbd5e1;background:var(--field);color:var(--h);border-radius:.75rem;padding:.75rem 1rem;font:inherit;font-size:1.125rem}
html.dark .field{border-color:#334155}.field:focus{border-color:var(--blue);outline:none;box-shadow:0 0 0 3px rgba(37,99,235,.3)}
.addbtn{margin-top:.75rem;background:none;border:0;color:var(--link);font:inherit;font-size:.875rem;font-weight:500;cursor:pointer;padding:0}.addbtn:hover{text-decoration:underline}
.actions{display:flex;flex-wrap:wrap;gap:.75rem;margin-top:1.25rem}
.btn{border-radius:.75rem;padding:.75rem 1.5rem;font:inherit;font-weight:600;cursor:pointer;border:1px solid transparent;text-decoration:none;display:inline-flex}
.btn.p{background:var(--blue);color:#fff}.btn.p:hover{background:var(--blue2)}
.btn.s{background:var(--card);border-color:#cbd5e1;color:var(--fg)}html.dark .btn.s{border-color:#334155}.btn.s:hover{background:var(--soft)}
.sm{border:1px solid #bfdbfe;background:var(--card);color:var(--blue2);border-radius:.5rem;padding:.375rem .75rem;font:inherit;font-size:.875rem;font-weight:500;cursor:pointer}html.dark .sm{border-color:#475569;color:#93c5fd}
.out{margin-top:1.25rem}.hint{font-size:.875rem;color:var(--muted)}
.err{border:1px solid #fecaca;background:#fef2f2;color:#991b1b;border-radius:.75rem;padding:.75rem 1rem;font-size:.875rem;margin:0}
html.dark .err{background:#450a0a;border-color:#7f1d1d;color:#fecaca}
.res{background:var(--res);border-radius:.75rem;padding:1rem}
.res .lab{margin:0;font-size:.875rem;font-weight:500;color:var(--muted)}
.res .num{margin:.25rem 0 0;font-size:2.25rem;font-weight:700;color:var(--blue);word-break:break-all;font-variant-numeric:tabular-nums}
html.dark .res .num{color:#60a5fa}
.res .btns{display:flex;flex-wrap:wrap;gap:.5rem;margin-top:.75rem}
.steps{margin-top:1.5rem;display:grid;gap:1.5rem}.steps h3{margin:0;font-size:1rem;font-weight:600;color:var(--h)}
.steps p,.steps li{margin:.375rem 0 0;line-height:1.75}.steps ul{list-style:none;padding:0;margin:.375rem 0 0}
.note{margin-top:.75rem;font-size:.875rem;font-weight:500;color:#15803d}
.hist{margin-top:1.5rem;border-top:1px solid var(--line);padding-top:1rem}
.hist .row{display:flex;justify-content:space-between;align-items:center}.hist h2{margin:0;font-size:1rem;font-weight:600;color:var(--h)}
.hist ul{list-style:none;padding:0;margin:.5rem 0 0;display:flex;flex-wrap:wrap;gap:.5rem}
.hist li button{border:1px solid var(--line);background:none;color:var(--fg);border-radius:.5rem;padding:.375rem .75rem;font:inherit;font-size:.875rem;cursor:pointer}.hist li button:hover{border-color:var(--blue);color:var(--link)}
.hist .clr{background:none;border:0;font:inherit;font-size:.875rem;color:var(--muted);cursor:pointer}.hist .clr:hover{text-decoration:underline}
.hist small{display:block;margin-top:.5rem;font-size:.75rem;color:var(--muted)}
.content{padding-top:1rem;padding-bottom:2rem}.content.pg{padding-top:2.5rem;padding-bottom:2.5rem}
.content h2{margin:3rem 0 0;font-size:1.5rem;font-weight:700;letter-spacing:-.01em;color:var(--h)}
.content h3{margin:1.5rem 0 0;font-size:1.125rem;font-weight:600;color:var(--h)}
.content p{margin:.75rem 0 0;line-height:1.75}.content ul{margin:.75rem 0 0;padding-left:1.5rem;line-height:1.75;list-style:disc}.content ol{margin:.75rem 0 0;padding-left:1.5rem;line-height:1.75}
.content a{color:var(--link);font-weight:500;text-decoration:underline;text-underline-offset:2px}
.content h1+p{margin-top:1rem}.content h1+h2{margin-top:1.5rem}
.eq{margin:.75rem 0 0;border-radius:.75rem;background:var(--code);padding:.75rem 1rem;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:.875rem;line-height:1.75}
.content p.eq{margin-top:.75rem}
table{margin-top:1rem;width:100%;border-collapse:collapse;text-align:left;font-size:.875rem}th,td{border:1px solid var(--line);padding:.5rem .75rem}th{background:var(--soft);font-weight:600}
.ov{overflow-x:auto}
details.card{padding:.75rem 1rem;margin-top:.75rem}details summary{display:flex;justify-content:space-between;gap:1rem;cursor:pointer;list-style:none;font-weight:600;color:var(--h)}
details summary::-webkit-details-marker{display:none}details summary span{color:var(--link);transition:transform .15s}details[open] summary span{transform:rotate(45deg)}
details p{margin:.5rem 0 0!important;line-height:1.75;color:var(--fg)}
.content ul.tools{list-style:none;padding:0;margin:1.5rem 0 0;display:grid;gap:1rem}
.content ul.tools li{margin:0;padding:0}
.content ul.tools a{display:block;height:100%;padding:1.25rem;text-decoration:none;font-weight:400;color:var(--fg)}.content ul.tools a:hover{border-color:var(--blue)}
.content ul.tools b{display:block;font-size:1rem;font-weight:600;color:var(--h)}.content ul.tools span{display:block;margin-top:.375rem;font-size:.875rem;line-height:1.5;color:var(--muted)}
.content .lead{max-width:none;margin:1rem 0 0;font-size:1.125rem;line-height:1.75;color:var(--fg)}
footer{margin-top:2rem;border-top:1px solid var(--line);background:var(--soft)}
footer .wrap{display:grid;gap:2rem;padding-top:2.5rem;padding-bottom:2.5rem}
footer p{margin:0}footer .t{font-weight:700;color:var(--h)}footer .d{margin-top:.5rem;max-width:28rem;font-size:.875rem;line-height:1.5;color:var(--muted)}
footer ul{list-style:none;margin:.5rem 0 0;padding:0;font-size:.875rem;display:grid;gap:.25rem}footer li a{color:var(--muted);text-decoration:none}footer li a:hover{color:var(--link);text-decoration:underline}
footer .copy{border-top:1px solid var(--line);padding:1rem;text-align:center;font-size:.75rem;color:var(--muted)}
.center{text-align:center;padding-top:5rem;padding-bottom:5rem}.center .btn{margin-top:1.5rem}
@media(min-width:640px){.grid{grid-template-columns:1fr 1fr}.hero h1{font-size:2.25rem}.hero h1.big{font-size:3rem}.calc{padding:1.5rem}.content ul.tools{grid-template-columns:1fr 1fr}footer .wrap{grid-template-columns:1fr 1fr}.hero .w4{padding-top:3rem;padding-bottom:3rem}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}